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CVE-2026-53209: Bluetooth: hci_sync: reject oversized Broadcast Announcement prepend

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-25 · updated 2026-10-19
• Weakness: CWE-787

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: reject oversized Broadcast Announcement prepend Existing advertising instances can already hold the maximum extended advertising payload. When hci_adv_bcast_annoucement() prepends the Broadcast Announcement service data to that payload, the combined data may no longer fit in the temporary buffer used to rebuild the advertising data. Reject that case before copying the existing payload and report the failure through the device log. This keeps the existing advertising data intact and avoids overrunning the temporary buffer.

Affected products

• Linux kernel: from 6.1.142 before 6.1.176; from 6.6.94 before 6.6.143; from 6.12.34 before 6.12.94; from 6.15.3 before 6.16; from 6.16.1 before 6.18.36; from 6.19 before 7.0.13 — fixed in 6.1.176, 6.12.94, 6.16, 6.18.36, 6.6.143, 7.0.13

How to fix

Upgrade to a fixed version: Linux kernel 6.1.176, 6.12.94, 6.16, 6.18.36. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/02f50e8bb69f9b22516163a09922f5537d3b12d1
• https://git.kernel.org/stable/c/10b0e832cc05d7aef4b92bed912cbd4a395d0862
• https://git.kernel.org/stable/c/1338ee049a8910ba6c9cee963920e978e6893c7d
• https://git.kernel.org/stable/c/5c65b96b549ea2dcfde497436bf9e048deb87758
• https://git.kernel.org/stable/c/cdd8bbdbee763fdf5bf343e6f7d4e79347739f62
• https://git.kernel.org/stable/c/dafc9f57140e66a10945127aa7433c3d715dc253

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